AudioPolicyInterface.h revision e552edb33fb5873179ae0a46d9579d1103eb13c6 
1/*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_AUDIOPOLICYINTERFACE_H
18#define ANDROID_AUDIOPOLICYINTERFACE_H
19
20#include <media/AudioSystem.h>
21#include <media/ToneGenerator.h>
22#include <utils/String8.h>
23
24#include <hardware_legacy/AudioSystemLegacy.h>
25#include <hardware/audio_policy.h>
26
27namespace android_audio_legacy {
28    using android::Vector;
29    using android::String8;
30    using android::ToneGenerator;
31
32// ----------------------------------------------------------------------------
33
34// The AudioPolicyInterface and AudioPolicyClientInterface classes define the communication interfaces
35// between the platform specific audio policy manager and Android generic audio policy manager.
36// The platform specific audio policy manager must implement methods of the AudioPolicyInterface class.
37// This implementation makes use of the AudioPolicyClientInterface to control the activity and
38// configuration of audio input and output streams.
39//
40// The platform specific audio policy manager is in charge of the audio routing and volume control
41// policies for a given platform.
42// The main roles of this module are:
43//   - keep track of current system state (removable device connections, phone state, user requests...).
44//   System state changes and user actions are notified to audio policy manager with methods of the AudioPolicyInterface.
45//   - process getOutput() queries received when AudioTrack objects are created: Those queries
46//   return a handler on an output that has been selected, configured and opened by the audio policy manager and that
47//   must be used by the AudioTrack when registering to the AudioFlinger with the createTrack() method.
48//   When the AudioTrack object is released, a putOutput() query is received and the audio policy manager can decide
49//   to close or reconfigure the output depending on other streams using this output and current system state.
50//   - similarly process getInput() and putInput() queries received from AudioRecord objects and configure audio inputs.
51//   - process volume control requests: the stream volume is converted from an index value (received from UI) to a float value
52//   applicable to each output as a function of platform specific settings and current output route (destination device). It
53//   also make sure that streams are not muted if not allowed (e.g. camera shutter sound in some countries).
54//
55// The platform specific audio policy manager is provided as a shared library by platform vendors (as for libaudio.so)
56// and is linked with libaudioflinger.so
57
58
59//    Audio Policy Manager Interface
60class AudioPolicyInterface
61{
62
63public:
64    virtual ~AudioPolicyInterface() {}
65    //
66    // configuration functions
67    //
68
69    // indicate a change in device connection status
70    virtual status_t setDeviceConnectionState(audio_devices_t device,
71                                          AudioSystem::device_connection_state state,
72                                          const char *device_address) = 0;
73    // retrieve a device connection status
74    virtual AudioSystem::device_connection_state getDeviceConnectionState(audio_devices_t device,
75                                                                          const char *device_address) = 0;
76    // indicate a change in phone state. Valid phones states are defined by AudioSystem::audio_mode
77    virtual void setPhoneState(int state) = 0;
78    // force using a specific device category for the specified usage
79    virtual void setForceUse(AudioSystem::force_use usage, AudioSystem::forced_config config) = 0;
80    // retrieve current device category forced for a given usage
81    virtual AudioSystem::forced_config getForceUse(AudioSystem::force_use usage) = 0;
82    // set a system property (e.g. camera sound always audible)
83    virtual void setSystemProperty(const char* property, const char* value) = 0;
84    // check proper initialization
85    virtual status_t initCheck() = 0;
86
87    //
88    // Audio routing query functions
89    //
90
91    // request an output appropriate for playback of the supplied stream type and parameters
92    virtual audio_io_handle_t getOutput(AudioSystem::stream_type stream,
93                                        uint32_t samplingRate,
94                                        audio_format_t format,
95                                        audio_channel_mask_t channelMask,
96                                        AudioSystem::output_flags flags,
97                                        const audio_offload_info_t *offloadInfo) = 0;
98    // indicates to the audio policy manager that the output starts being used by corresponding stream.
99    virtual status_t startOutput(audio_io_handle_t output,
100                                 AudioSystem::stream_type stream,
101                                 int session = 0) = 0;
102    // indicates to the audio policy manager that the output stops being used by corresponding stream.
103    virtual status_t stopOutput(audio_io_handle_t output,
104                                AudioSystem::stream_type stream,
105                                int session = 0) = 0;
106    // releases the output.
107    virtual void releaseOutput(audio_io_handle_t output) = 0;
108
109    // request an input appropriate for record from the supplied device with supplied parameters.
110    virtual audio_io_handle_t getInput(int inputSource,
111                                    uint32_t samplingRate,
112                                    audio_format_t format,
113                                    audio_channel_mask_t channelMask,
114                                    AudioSystem::audio_in_acoustics acoustics) = 0;
115    // indicates to the audio policy manager that the input starts being used.
116    virtual status_t startInput(audio_io_handle_t input) = 0;
117    // indicates to the audio policy manager that the input stops being used.
118    virtual status_t stopInput(audio_io_handle_t input) = 0;
119    // releases the input.
120    virtual void releaseInput(audio_io_handle_t input) = 0;
121
122    //
123    // volume control functions
124    //
125
126    // initialises stream volume conversion parameters by specifying volume index range.
127    virtual void initStreamVolume(AudioSystem::stream_type stream,
128                                      int indexMin,
129                                      int indexMax) = 0;
130
131    // sets the new stream volume at a level corresponding to the supplied index for the
132    // supplied device. By convention, specifying AUDIO_DEVICE_OUT_DEFAULT means
133    // setting volume for all devices
134    virtual status_t setStreamVolumeIndex(AudioSystem::stream_type stream,
135                                          int index,
136                                          audio_devices_t device) = 0;
137
138    // retrieve current volume index for the specified stream and the
139    // specified device. By convention, specifying AUDIO_DEVICE_OUT_DEFAULT means
140    // querying the volume of the active device.
141    virtual status_t getStreamVolumeIndex(AudioSystem::stream_type stream,
142                                          int *index,
143                                          audio_devices_t device) = 0;
144
145    // return the strategy corresponding to a given stream type
146    virtual uint32_t getStrategyForStream(AudioSystem::stream_type stream) = 0;
147
148    // return the enabled output devices for the given stream type
149    virtual audio_devices_t getDevicesForStream(AudioSystem::stream_type stream) = 0;
150
151    // Audio effect management
152    virtual audio_io_handle_t getOutputForEffect(const effect_descriptor_t *desc) = 0;
153    virtual status_t registerEffect(const effect_descriptor_t *desc,
154                                    audio_io_handle_t io,
155                                    uint32_t strategy,
156                                    int session,
157                                    int id) = 0;
158    virtual status_t unregisterEffect(int id) = 0;
159    virtual status_t setEffectEnabled(int id, bool enabled) = 0;
160
161    virtual bool isStreamActive(int stream, uint32_t inPastMs = 0) const = 0;
162    virtual bool isStreamActiveRemotely(int stream, uint32_t inPastMs = 0) const = 0;
163    virtual bool isSourceActive(audio_source_t source) const = 0;
164
165    //dump state
166    virtual status_t    dump(int fd) = 0;
167
168    virtual bool isOffloadSupported(const audio_offload_info_t& offloadInfo) = 0;
169};
170
171
172// Audio Policy client Interface
173class AudioPolicyClientInterface
174{
175public:
176    virtual ~AudioPolicyClientInterface() {}
177
178    //
179    // Audio HW module functions
180    //
181
182    // loads a HW module.
183    virtual audio_module_handle_t loadHwModule(const char *name) = 0;
184
185    //
186    // Audio output Control functions
187    //
188
189    // opens an audio output with the requested parameters. The parameter values can indicate to use the default values
190    // in case the audio policy manager has no specific requirements for the output being opened.
191    // When the function returns, the parameter values reflect the actual values used by the audio hardware output stream.
192    // The audio policy manager can check if the proposed parameters are suitable or not and act accordingly.
193    virtual audio_io_handle_t openOutput(audio_module_handle_t module,
194                                         audio_devices_t *pDevices,
195                                         uint32_t *pSamplingRate,
196                                         audio_format_t *pFormat,
197                                         audio_channel_mask_t *pChannelMask,
198                                         uint32_t *pLatencyMs,
199                                         audio_output_flags_t flags,
200                                         const audio_offload_info_t *offloadInfo = NULL) = 0;
201    // creates a special output that is duplicated to the two outputs passed as arguments. The duplication is performed by
202    // a special mixer thread in the AudioFlinger.
203    virtual audio_io_handle_t openDuplicateOutput(audio_io_handle_t output1, audio_io_handle_t output2) = 0;
204    // closes the output stream
205    virtual status_t closeOutput(audio_io_handle_t output) = 0;
206    // suspends the output. When an output is suspended, the corresponding audio hardware output stream is placed in
207    // standby and the AudioTracks attached to the mixer thread are still processed but the output mix is discarded.
208    virtual status_t suspendOutput(audio_io_handle_t output) = 0;
209    // restores a suspended output.
210    virtual status_t restoreOutput(audio_io_handle_t output) = 0;
211
212    //
213    // Audio input Control functions
214    //
215
216    // opens an audio input
217    virtual audio_io_handle_t openInput(audio_module_handle_t module,
218                                        audio_devices_t *pDevices,
219                                        uint32_t *pSamplingRate,
220                                        audio_format_t *pFormat,
221                                        audio_channel_mask_t *pChannelMask) = 0;
222    // closes an audio input
223    virtual status_t closeInput(audio_io_handle_t input) = 0;
224    //
225    // misc control functions
226    //
227
228    // set a stream volume for a particular output. For the same user setting, a given stream type can have different volumes
229    // for each output (destination device) it is attached to.
230    virtual status_t setStreamVolume(AudioSystem::stream_type stream, float volume, audio_io_handle_t output, int delayMs = 0) = 0;
231
232    // invalidate a stream type, causing a reroute to an unspecified new output
233    virtual status_t invalidateStream(AudioSystem::stream_type stream) = 0;
234
235    // function enabling to send proprietary informations directly from audio policy manager to audio hardware interface.
236    virtual void setParameters(audio_io_handle_t ioHandle, const String8& keyValuePairs, int delayMs = 0) = 0;
237    // function enabling to receive proprietary informations directly from audio hardware interface to audio policy manager.
238    virtual String8 getParameters(audio_io_handle_t ioHandle, const String8& keys) = 0;
239
240    // request the playback of a tone on the specified stream: used for instance to replace notification sounds when playing
241    // over a telephony device during a phone call.
242    virtual status_t startTone(ToneGenerator::tone_type tone, AudioSystem::stream_type stream) = 0;
243    virtual status_t stopTone() = 0;
244
245    // set down link audio volume.
246    virtual status_t setVoiceVolume(float volume, int delayMs = 0) = 0;
247
248    // move effect to the specified output
249    virtual status_t moveEffects(int session,
250                                     audio_io_handle_t srcOutput,
251                                     audio_io_handle_t dstOutput) = 0;
252
253};
254
255extern "C" AudioPolicyInterface* createAudioPolicyManager(AudioPolicyClientInterface *clientInterface);
256extern "C" void destroyAudioPolicyManager(AudioPolicyInterface *interface);
257
258
259}; // namespace android
260
261#endif // ANDROID_AUDIOPOLICYINTERFACE_H
262